In cataract surgery on the eye, after the lens is removed, a jagged edge of cortical material or cortex is left in the eye. This cortical material is removed by an instrument known as an irrigation and aspiration (I/A) handpiece. The I/A handpiece consists of two cannulas or tubes. The cortical material is aspirated under vacuum through one cannula to remove it. Simultaneously, an irrigating fluid, such as a saline solution, flows through the other cannula to prevent the material in the eye from drying and collapsing and to assist in the removal of the cortical material. The cannulas may be adjacent or concentric. When concentric, the inner cannula generally comprises the aspiration cannula and the outer cannula the irrigation cannula.
Commercially available I/A handpieces having concentric cannulas fall generally into two types. A first type is reusable after sterilization in an autoclave. This type must be disassembled to be cleaned and is fairly expensive to manufacture. A second type is disposable and cheaper to manufacture.